"Forestry Bureau. ”

At less than ten o'clock, Cui Luyi and Zhang Chunhe, who were in charge of tracking electromagnetic wave signals, returned to the bureau, went directly to Lin Jia's office, and put a red radio about the size of a Xinhua dictionary used by students on the desk in front of Lin Jia.

"Is this the one, how did you get your hands on it, didn't it attract the attention of its owner?"

"This is it. Cui Luyi said: "After we quietly followed the three old people to leave the labor park before eight o'clock, the owner of the radio, that is, the old lady who was nearly 70 years old, went directly to a store specializing in small electrical appliances. I told the clerk that there was something wrong with the radio, and there was always unbearable noise from time to time, so I wanted to replace it with a new one.

It happened that the store was engaged in a trade-in activity, so I put up 20 yuan and exchanged it for a new one. We then bought it back for fifty dollars as radio enthusiasts. ”

Lin Jia took a closer look at the radio in his hand, in fact, it was the kind of player that can be seen everywhere in the hands of the old man on the street, with a memory card inside, which can store a large amount of content that the owner likes, and at the same time has a radio function.

"Have you investigated her identity?"

"Checked. Zhang Chunhe took out a piece of printer paper from his handbag and handed it to Lin Jia to explain: "This is the information we transferred from the police station in the jurisdiction where the old man is located. The old lady was a middle school music teacher before she retired, and her husband used to be a manager of a listed company. The couple has a daughter in her 40s, and both daughters and sons-in-law are secondary school teachers. For the time being, nothing suspicious was found in their family. ”

"What about electromagnetic wave signals, is there anything special?"

"The Forestry Bureau may not believe it. Cui Luyi took off the receiving device on her wrist similar to a watch, and pressed the playback button in front of Lin Jia, and suddenly there was a regular and familiar ticking sound from inside.

"No, it's the most common Morse code?"

At first, we thought something was wrong, but when we compared the Morse code and translated it, we couldn't help but believe it. ”

While talking about Cui Luyi, she picked up the pen on Lin Jia's desktop and translated the tick-tick signals from the receiving device on a piece of paper: 7845, 2436, 7721, 2439, 5418, 4327, .......

"Sending instructions in the common Morse code, which is also the most common way?"

At this point, Lin Jia also understood that the radio in front of him, strictly speaking, should be an electromagnetic wave signal emitted by the player, and it was not a high-level password. Otherwise, it would be impossible to translate such a clear and regular result in ordinary Morse code.

Judging from the results of the translation, this is another method that was very popular in the last century, before the popularization of television, and espionage organizations used to send instructions to hidden spies through radio broadcasting. Anyone of a certain age has had a similar experience, in the process of tuning the radio, at every turn will hear a flat tone, clear words, but not a standard Mandarin accent, the content is just a set of simple numbers broadcast.

However, despite its age, it is very effective. Because each set of numbers represents the pages and lines of a certain book, the words, and so on.

For example, the first set of numbers 7845 translated by Cui Luyi refers to the 7th page of a book, or the 5th word in the 4th line of page 78. By analogy, 2436 refers to the sixth word on page 2 or page 24, line 3. Finally, when these words are combined, it is the content of the instructions issued by the spy organization to the sleepers.

The advantage of this approach is that as long as you don't know which book the spy organization is using, no matter how good you are at cryptography, you will never be able to decipher the content of the messages they send.

"It seems that the idea of analyzing the content of the information transmitted by electromagnetic waves to confirm whether it is a contact with Yang Yuting is not possible. ”

Lin Jia casually opened the player in his hand, and there was no interference sound when playing the contents of the memory card. But when she turned to the radio function and turned the frequency adjustment button to 1001HZ, a screeching sound appeared.

"Leave it to the technical department, and let them take it apart to see if they can trace the source of the electronic components used in it that send strong electromagnetic signals. ”

"Yes, Forest Bureau. ”

Zhang Chunhe took it and turned around and walked out. Cui Luyi, who stayed behind, hesitated for a while and asked: "Forest Bureau, if you want to know if it is an order issued to Yang Yuting, you can only take action against Yang Yuting." ”

"It doesn't mean much, as long as Yang Yuting doesn't admit it, we can't be sure of anything. ”

"Forest Bureau, even if Yang Yuting is a professor and reads a lot of books, it is also limited, as long as you work hard, you should always find it, right?"

"Hehe, I remember seeing such a case when I was in training. The same way was used to transmit instructions, and the hidden spy was finally caught, but after interrogation, the man was illiterate. ”

"How is that possible?"

"What's impossible? The spy had memorized an article of less than two thousand words by rote under the advice of someone else, and all the instructions the Order had given him were from the text of that article. If the spy hadn't finally confessed, no one would have known what was going on. ”

"Do you want to continue to monitor Yang Yuting next, Forest Bureau?"

Yang Yuting, who was abandoned by his organization, has almost become a chicken rib for Lin Jia. In addition to what the National Security Bureau has already grasped, such as what organization Yang Yuting is behind it, which country and which department it belongs to, and so on, it is estimated that it is impossible to get more information. If you don't catch it, it's useless to continue to keep Yang Yuting. The possibility of using Yang Yuting to fish out its online line no longer exists.

Hearing Cui Luyi's question, Lin Jia hesitated for a while, and finally nodded and said, "Wait a little longer, let's see who this person or organization that makes electromagnetic wave emitters is contacting in this way." Once this is determined, Yang Yuting will be arrested immediately. Then Lin Jia said to Cui Luyi: "You and Chunhe will investigate first, who secretly did something to this radio." If it is not necessary, try not to alarm the old lady's family. ”

"Yes, Forest Bureau. ”

didn't let Lin Jia wait too long, and at three o'clock in the afternoon, a group of people who were arranged by her to replace Cui Luyi and Zhang Chunhe reported to Lin Jia: "Forest Bureau, Yang Yuting has already booked a ticket to leave tomorrow morning." ”

"Where are the others?"

"Since I came back from Labor Park in the morning, I have never left the University of Science and Technology. ”

"Okay, I got it. You continue to monitor and report on Yang Yuting's movements at any time. ”

"Yes, Forest Bureau. ”

Immediately, Lin Jia dialed the phone number of Ling Zhan of the Serious Crime Team: "Team Ling, it's me, Lin Jia." ”

"Forestry Bureau, please instruct. ”

"Yang Yuting has just booked a ticket to leave tomorrow morning, and in order to paralyze the unknown person A, it is inconvenient for us to come forward for the time being. Therefore, please ask the Ling team to send someone to control Yang Yuting first on the grounds that Yang Wenjing and Yang Yutang are two suspects in the criminal case. ”

Immediately, Lin Jia told Ling Zhan on the phone about the content of the signals received by Cui Luyi and Zhang Chunhe through the special electromagnetic wave receiving device on their wrists, and instructed Ling Zhan to pay more attention to the books that were placed on his hand or had obvious traces of frequent flipping when searching Yang Yuting's residence and office.

"Okay, I'll take someone right away. Before hanging up the phone, Ling Zhan asked again: "Forest Bureau, do you want to send Yang Yuting to the National Security Bureau after arresting him?"

"Not for the time being, I'll arrange for someone to go to the serious crime team to interrogate him. ”